@article{10_4064_sm156_2_6,
     author = {Eungil Ko},
     title = {On w-hyponormal operators},
     journal = {Studia Mathematica},
     pages = {165--175},
     publisher = {mathdoc},
     volume = {156},
     number = {2},
     year = {2003},
     doi = {10.4064/sm156-2-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm156-2-6/}
}